The present invention relates generally to tomosynthesis systems, and more specifically to a system and method for continuous scanning in tomosynthesis systems.
Tomosynthesis systems are often used in the field of medicine to generate three-dimensional (3D) images of an object. A typical tomosynthesis system comprises an x-ray source, an x-ray detector, motion controller and a processing circuit. The x-ray source is moved along a path and projects x-rays on the object, usually a patient. The x-ray detector detects the x-rays and generates a corresponding tomosynthesis data set comprising projection radiographs. The processing unit processes the projection radiograph to generate a 3D image of the object.
One approach for projecting x-rays on the object is the step and shoot approach. In this approach, the x-ray source is moved and pointed at a position on the object. X-rays are projected on the position and a projection radiograph is acquired. The x-ray source is then moved to a second position and a second projection radiograph is acquired. The x-ray source is thus moved to several positions relative to the object to acquire a set of projection radiographs. The projection radiographs are then processed to obtain a 3D image.
In general, it is desirable to keep the imaged object at a stationary position while acquiring the projection radiographs. To minimize object movement, the time required for the acquisition (“acquisition time”) of the projection radiographs needs to be reduced. In the step and shoot method, the acquisition time is considerable large as the acquisition time is the sum of the exposure time for each position and the time taken by the x-ray source to move to various positions.
Another problem with the step and shoot approach is images generated are blurred due to system vibration. To reduce system vibration, a short period of time is required for residual vibration to dampen to an acceptable level before acquiring the projection radiograph. The short period of time further adds to the acquisition time, which is also undesirable.
It is therefore be desirable to minimize the acquisition time for generating 3D images by a tomosynthesis system while reducing the system vibration.